Comment

The title compound, (I), was prepared as part of our study of the supramolecular arrangements of imine and amido compounds.

In the molecules of (I) (Fig. 1), the bond distances (Table 1) in the acyclic acylhydrazone fragment C11-C21 are all standard (Allen et al., 1987), and there is no evidence for any bond fixation within the aryl rings. Hence, the conventional representation (I) is entirely appropriate. This central spacer unit is nearly planar, as shown by the key torsional angles, with a trans planar H-N-C=O fragment, as expected, and an E configuration at the C1=N1 bond. However, the aryl rings are both twisted out of this plane, making dihedral angles of 38.9 (2) and 43.3 (2)°, while the nitro group is twisted out of the plane of the adjacent aryl ring by 33.7 (2)°. Within the spacer unit C11-C21, the intrachain bond angles are all less than 120°.

The molecules of (I) are linked into sheets by one N-HO hydrogen bond and two C-HO hydrogen bonds, one of which utilizes the carbonyl O atom as acceptor, while the other utilizes a nitro O atom. Hydrazone atom N2 and methine atom C1 in the molecule at (x, y, z) both act as hydrogen-bond donors to carbonyl atom O2 in the molecule at (x, -1 + y, z), thus generating by translation a C(4)C(6)[R₂¹(6)] chain of rings (Bernstein et al., 1995) running parallel to the [010] direction (Fig. 2). It may be noted here that analogous C(4) motifs are rather common in both carboxamides and sulfonamides.

In addition, aryl atom C26 in the molecule at (x, y, z) acts as hydrogen-bond donor to nitro atom O22 in the molecule at (1 - x, -y, - + z), thereby forming a C(11) chain, generated by the 2₁ screw axis along (, 0, z) and running parallel to the [001] direction (Fig. 3). The combination of the simple [001] chains and the [010] chains of rings then generates a complex (100) sheet (Fig. 4). This sheet lies in the domain 0.21 < x < 0.79 and a second such sheet, related to the first by the action of the glide planes, lies in the domain 0.71 < x < 1.29. However, there are no direction-specific interactions between adjacent sheets: in particular, C-H(arene) hydrogen bonds, aromatic - stacking interactions, and iodo-nitro interactions are all absent.

Figure 1 The molecule of compound (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2 Part of the crystal structure of compound (I), showing the formation of a C(4)C(6)[R21(6)] chain of rings along [010]. For the sake of clarity, the H atoms on the aryl rings have been omitted. Atoms marked with an asterisk (*) or a hash (#) are at the symmetry positions (x, -1 + y, z) and (x, 1 + y, z), respectively.

Figure 3 Part of the crystal structure of compound (I), showing the formation of a C(11) chain along [001]. For the sake of clarity, the H atoms not involved in the motif shown have been omitted. Atoms marked with an asterisk (*), a hash (#) or an ampersand (&) are at the symmetry positions (1 - x, -y, - + z), (1 - x, -y, + z) and (x, y, 1 + z), respectively.

Figure 4 Stereoview of part of the crystal structure of compound (I), showing the formation of a (100) sheet. For the sake of clarity, the H atoms not involved in the motifs shown have been omitted.

Experimental

The title compound was prepared by reaction of 2-nitrobenzaldehyde hydrazone with 2-iodobenzoyl chloride. A solution containg 2 mmol of each reactant in 1,2-dichloroethane (20 ml) was heated under reflux for 1 h; the mixture was cooled and the solvent was removed under reduced pressure. The solid residue was crystallized initially from ethanol, and crystals suitable for single-crystal X-ray diffraction were obtained by slow evaporation of a solution in ethanol and 2-propanol [1/1 (v/v), m.p. > 520 K]. IR (KBr disk): 1680 cm^-1.

Crystal data

C14H10IN3O3 Mr = 395.15 Orthorhombic, P c a 21 a = 21.6122 (8) Å b = 5.0393 (2) Å c = 12.7868 (5) Å V = 1392.62 (9) Å3 Z = 4 Dx = 1.885 Mg m-3 Mo K radiation Cell parameters from 2783 reflections = 3.7-27.5° = 2.31 mm-1 T = 120 (2) K Plate, green 0.28 × 0.08 × 0.05 mm

Data collection

Bruker-Nonius KappaCCD diffractometer and scans Absorption correction: multi-scan(SADABS; Sheldrick, 2003)Tmin = 0.564, Tmax = 0.893 12100 measured reflections 2783 independent reflections 2579 reflections with I > 2(I) Rint = 0.036 max = 27.5° h = -27 25 k = -6 6 l = -16 14

Refinement

Refinement on F2 R[F2 > 2(F2)] = 0.026 wR(F2) = 0.054 S = 1.05 2783 reflections 190 parameters H-atom parameters constrained w = 1/[2(Fo2) + (0.0068P)2 + 2.6684P] where P = (Fo2 + 2Fc2)/3 (/)max = 0.001 max = 0.62 e Å-3 min = -0.64 e Å-3 Absolute structure: Flack (1983), 1119 Friedel pairs Flack parameter: -0.01 (2)

Table 1 Selected geometric parameters (Å, °) C11-C1 1.476 (5) C1-N1 1.286 (5) N1-N2 1.396 (5) N2-C2 1.358 (6) C2-O2 1.233 (5) C2-C21 1.482 (5) C22-I22 2.107 (4) C11-C1-N1 118.3 (3) C1-N1-N2 113.2 (3) N1-N2-C2 119.1 (4) N2-C2-O2 123.5 (4) O2-C2-C21 122.2 (4) N2-C2-C21 114.2 (3) C12-C11-C1-N1 -151.3 (4) C11-C1-N1-N2 -175.4 (3) C1-N1-N2-C2 -174.4 (4) N1-N2-C2-C21 176.2 (3) N2-C2-C21-C22 138.2 (4) C11-C12-N12-O11 18.6 (5)

Table 2 Hydrogen-bond geometry (Å, °) D-HA D-H HA DA D-HA N2-H2O2i 0.88 1.98 2.820 (5) 159 C1-H1O2i 0.95 2.27 3.082 (5) 142 C26-H26O22ii 0.95 2.39 3.169 (6) 139 Symmetry codes: (i) x, y-1, z; (ii) .

All H atoms were located in difference maps and subsequently treated as riding atoms, with distances C-H = 0.95 Å and N-H = 0.88 Å, and with U_iso(H) = 1.2U_eq(C,N). The correct orientation of the structure with respect to the polar-axis direction c (Jones, 1986) was established using the Flack (1983) parameter.

Data collection: COLLECT (Hooft, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).